Toolbox Talk

Portable Generator Electrical Safety

TBT-PLT-044

Portable generators provide temporary electrical power on construction sites where mains supply is not available. They introduce risks of electrocution, carbon monoxide poisoning, fire from fuel, and noise exposure. Incorrect connection or earthing can make the generator a serious electrical hazard. This talk covers the safe setup, operation, and connection of portable generators on site.

Key Hazards
Electrocution from unearthed or incorrectly connected portable generators
Carbon monoxide poisoning from generators running in enclosed or sheltered areas
Fire from fuel leaks or refuelling a running generator with a hot engine
Backfeed into the mains supply if the generator is connected without proper isolation
Control Measures
  • Position generators outdoors in well-ventilated areas away from building openings and air intakes.
  • Ensure the generator has a proper earth connection installed by a competent electrician.
  • Use 110V centre-tapped earth systems for powering portable tools from the generator on site.
  • Protect all 230V outlets with a 30mA RCD and test the RCD before connecting any load.
  • Switch off the generator and allow it to cool before refuelling with diesel or petrol.
  • Never connect a portable generator to the mains supply without an approved changeover switch.
  • Inspect power cables, plugs, and sockets connected to the generator before each use.
  • Ensure the generator is rated for the total connected load and not overloaded during operation.
  • Keep generators on a level surface and secure them to prevent theft and unauthorised use.
Remember
  • Position generators outdoors in well-ventilated areas away from building openings at all times
  • A proper earth connection must be installed by a competent electrician before the generator is used
  • Use 110V centre-tapped earth systems for portable tools and 30mA RCD protection on 230V outlets
  • Switch off the generator and let it cool completely before any refuelling operation begins
  • Never connect a generator to the mains supply without an approved changeover switch fitted
  • Ensure the generator is rated for the total connected load and never overloaded during operation
Applicable Legislation: Electricity at Work Regulations 1989 · BS 7671 (IET Wiring Regulations) · PUWER 1998 · Health and Safety at Work etc. Act 1974
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